Electric rheostat.



PATENTED APR. 19, 1904.

R. W. BROWN. ELECTRIC RHEOSTAT. APPLICATION FILED APR. 21, 1903.

N0 MODEL.

PA'IENTED APR. 19, 1904.

R. w, BROWN. ELECTRIC RHEOSTAT. APPLICATION FILED APR. 21, 1903.

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UNITED STATES.

Fatented April 19, 1904.

PATENT FFICE.

ELECTRIC RHEQSTAT.

SPECIFICATION forming part of Letters Patent No. 757,880, dated April 19, 1904.

Application filed April 21, 1903.

To albwhom it may concern:

Be it known that I, ROY W. BRoWN,-a' citizen of the United States, and. a resident of the city of Amsterdam, New York, have invented a certain new and useful Improvement in Electric Rheostats, of which the following is a specification, referencebeing had to .the accompanying drawings, forming a part hereof. Y

My invention relates to rheostats; -and it has for its objectto provide a'simple and efficient means for Varying the current of anexternal circuit.

used to control'the motor or other translating device. The in vention is particularly designed to be used where there is more or; less shock and jar,

such as for controlling the motor of a street-' carmx The invention consists in providing a resistance body and contacts supported thereon at different points of the resistance body in order to connect more or less of the resistance-body in the circuit.

The invention alsoconsists in arranging the contacts on the resistance body so that the,

contacts at -the ends of the resistance body will alternately'make connection witha moving contact-piece.

The invention also consists informing a resistance body of carbon, such as graphite or ofa compositioncarbon andfother materials or of other substances. When formed of friable substances, means are provided for clamping the contacts thereto instead of bor-' ing or puncturing the resistance body, and

thereby greatly weakening it.

The invention also consists in providing a contact with a contact-shoe which is'hinged Serial No. 153,592. (No model.)

.the circuit connections of the invention.

' Referring to Fig. 1, 1 indicates a supporting-base. 2, 3, 4, and 5' are binding-posts mounted on the said base 1. The bindingposts have the usual form of a binding-screw for making electrical connections. In the upper end of the posts 2 and 4 there is secured a rod 6. In the same manner there is also secured to the upper end of the post 3 and another post 7 a second rod 8. A contact-piece '9 is adapted to move along the rods 6 and 8, which consists of fiber for purposes of insulation. The contact-piece 9 may, however, be formed of any other material, provided that the necessary insulation is provided for. Sleeves 10 and 11 are carried by the contact-piece and prevent anybinding of the contact-piece with the rods. Springs 12 and 13 are located on the rods 6 and 8 and between the contact-piece 9 and the posts 1 and7, so that when the contactpiece is moved along the rods the springs will be compressed and will tend to return the contact-piece to its normal position. A pair of contacts 14 and 15 are located in thecontactpiece 9. The contacts 14 and 15 consist of sleeves 16, which are secured in the cross-block of fiber. In each of the sleeves is located a plunger 17 adapted to move-freel'y'along the sleeve. ger outward, and a nut 19, located on the plungerrrod 20, regulates the extent of movement of the plunger. .A contact-shoe 21 is hinged to the plunger; which permits of free inovernentof the contact-shoe and causes it to make good connection with surfaces that A spring 18 tends toforcethe plundownward they make connections with the The resistance may be, moreover, greatly varied as to shape and arrangement of its parts. The lower ends of the rods 21 25 are connected together by a strip of metal 26. Contacts 27 2? 2'7 27 are'located on the ends of the rods 2% 25, while the remaining contacts 28. are

staggered along the rodthat is, the contacts on one of the rods are located nearer one end of that rod thanthe corresponding contacts located on the other red, as illustrated in Figs. 1 and 3. Vhen the contact-piece 9 is moved along the contacts on the resistance body, connections are made first with. the contacts 27 27 located at the upper end of the rods and the current then passes through the whole length of the two rods. As the contact-piece is moved farther along the resistance body one of the contact-shoes comes into contact with but one of the contacts located a short distance along the rod before leaving the'upper contact of the other rod. This reduces the length of the resistance body along which the current passes. As the contact-piece is moved still farther down the rods the other contact-shoe comes into contact with a contact located another step along'the other end of the resistance body. Connection is thus made between the terminal contacts and the resistance body, so as to cut out of an external circuit parts of the resistance body, and thereby reducing the resistance of the external circuit. When the'contact-piecereaches the lower end of its movement, the shoes make connection with lower contacts 27 27 and the resistance of the resistance body. iscompletely cut out of the circuit. The contacts carried by the resistance body have rods for securing them to the resistance body. The rod or shank passes through a hole bored through the resistance body and secured by a nut 30.- In order that a good connection may be made with the resistance body, a Washer 31 of non-' corrosive material, such'as aluminium, is closely pressed against the resistance body.

\Vhen the contact-piece 9 is moved to a pointsuch that the. resistance body is completely out out of the circuit, it is retained in that position by means 'of the retaining-magnet 32, which attracts and holds the armature 33, lo-

cated on the contact-piece 9. The electro' magnet 32 is connected in the circuit, so as to be energized, and thus retains the contactplece when the armature located on the moving contacts comes wlthin its field. of force.

A pushrbutton or other switch 34 is provided for either opening the circuit of the magnet or short-circuiting it in order that it may be' deencrgized and the contact-piece allowed to return to. Its normal position by the operation of'the springs 12 13. In the preferred form provided. An insulating-strip 36 is located 'over the contacts 14: and 15 to avoid all danger of short-circuiting of the contacts.

. In the modified form of my invention Iuse contact-heads, which may be clamped'to the resistance body. If the resistance body is bored or punctured, it is liable to break either while in. the process of manufacture of the rheostat or while it isbeing shipped or in the use of the device; The body being of friable nature, it is greatly weakened thereby. In

Figs. 3 and 4: I have illustrated contacts which of my invention the magnet is shor circuited. For operating the-contact-piece a handle 35 rs are secured by clamping them around the resistance body. The contact consists of a strip or contact-head 37, through which pass clampingbolts 38 .39. The clamping-bolts have screw-threads at one end ofeach of the bolts,

which is adapted to be screwed i'ntoithe strip 40, located at the back of the rod, and thereby securely fastening the contact-head or strip to the resistance body. In order to'makea good contactbetween the contact and the-resistance body, a strip of aluminium 41 is. located tween the resistance body and the back strip.

Any non-corrosive material may be'used-in place of the'strip of aluminium. The strips are securely clamped to the rods/12 43', which are mounted on the base-plate 1 and secured theretd by means of the bolts which pass.

through the base-plate-1. The lower ends of theresistance-rods may be provided with contacts,or a single contact-strip 44 may beused for connecting their lower ends together. A corresponding strip is located at the back of the resistance-rods, into which the bolts are screwed for" securing the strip to the resist ance body.

In Fig. 5 is illustrated the circuit connections-of the rh'eostat and the connections of the rheostat with an external circuit. The

rheostat maybe used as a controller for any electrical device. I have illustrated the rheostat in the diagram as being used in connection with a motor. The'resistance body is connected in the a'rmaturecircuit, and the magnet is connected in the field-circuit of the motor. When it is desired to start the, mo-

tor, the contact-piece is moved down, so new close the connection of the armaturecircuit.

45 with the main line, 46. through the whgle of the resistance body. The contact-piece in The invention can be varied in many ways without departing fromthe spirit thereof. The arrangement of the contacts maybe varied and the manner of connecting them to the resistance body without avoiding my invention.

What I claim, and desire to secure by Letters Patent, isas followsz 1. In a rheostatthe'combination of a resistance body, a movable contact-piece, contactpieces located and supported on the resistance body and arranged so'that as ,theinovable contact-piece is moved along the resistance parts-of the resistance body will be cut out of the-circuit,first apart atone end and then a part at the other end.

, 2. Ina rheostat the combination of a resist- .ance body, an external circuit, a movable contact-piece having two contacts connected directly to" the said external circuit, contact pieces supported by the said resistance body and arranged so as to make contact with the contact-pieces connected to the ends of the resistance body and then to make contact with a contact-piece at a point farther from one end of the resistance body and then to a contact-piece at a point farther from the other end as the movable contact-piece is moved over ance body composed -.of afriable material,-

i ternately on the'rods as.

rods andarrang'edso that the said contactpiece will make contact with thefcontacts althe contact --piece moves along the said contacts.

" 5. In a rheostat the combination with a pair of carbon rods, a movable contact-piece, con-v tacts supported on the said rods and arranged "so that the said contact-piece will make con tact with a contact on one rod and then with a contact on the other rod before passing from 'the contact of the first-named rod and so alternately as the contact-piece moves over the said contacts.

6. In-afrheostat the combination of a resist ance body, a movable contact-piece having a pair of terminal contacts contacts supported on the said resistance body and adapted to make contact with thesaid terminal contacts,

an electromagnet'for securing the said con tact-piece, and means'for deenerglzing the Sflld electromagnet.

sso

7 In a rheostat the combination of a resistance body, a movable contact-piece having two terminal contacts, guides for the said contactpiece, contacts connected to the said resistance body and adapted to make connection with the said terminal contacts, an electromagnet for securing the said movable contactpiece', a switch for deenergizing the said electromagnet, and a spring for causing the said contact-piece to return to itsnormal position. 8. In arheostat the combination of a resistance body, contacts supported on the said rc-- sistance body, a contact-piece consisting of an insulating-body, a pair of sleeves supponted' by the said insulating-body, plunge'rs,-springs for controlling the said plungers, contact-shoes hinged to the said plungersandadapted to make contact with two of the said contacts at any one time.

9. In a rheostat the combination of a resistance body,'contacts'supported on the said rcsistance body and consisting of a contact-piece and a non-corrosive piece and means for clamping the said pleces to the resistance body by .a means passing on the outside of the resistance body,'.and a movable means for making contact with thesaid contacts.

10. In a rheostat the combination of a resistance body, composed of carbon, contactcar- 'ried' by the said resistance body and consisting of a contact-pieceand a non-corrosive piece-for connecting the said contactpiece with the said resistance body and means for securing the said pieces to the resistance body by clamping the said piece around on the outside of the said resistance body, a movable means -for making contactwith the saidconta'cts.

11. v In a .rheo's'tat .the combination of a resist ance body, contacts located on -the said resistance body, bolts and a clamping-piece for clamping the said contacts around'on the outside of the said resistance body, non-corresive body located between the sai clamping:

piece and the said resistancebody.

' 12. In arheostat the combination of a resistance body consisting of a pair of rods composedof carbon, contacts located on the said rods, non-corrosive material located between the s'aid"c ontacts and the said carbon rods, a

contact-piece composed of an irisulating body,

a pair of spring-contacts, a pairof sleeves'and plungers located in the said sleeves and connected to the said contacts for guiding the same. V

'Signed in the'presence of two subscribing witnesses. ROY BROWN.

.W'itnesses:

' dorm Q. GEMPLER, 

